Why did TurboTax desktop delete my retun after days of incremental preparation and saving?

Attempted $20 credit card payment for Mich return.  Clicked on 'Credit card'.  TT atempted to save before going to CC com. (I guess).  Then said, can't do this. 'Unplug machinev (or device)."  I closed TT desktop.  Restart showed NO return.  Searched for file. Not there.  Says start over. Or go online.  What do I do? I've been using TT desktop for nearly 40 years.